Clear the texture element chain after drawing.

It was properly cleared after drawing water chains and sky chains, but I
had missed normal surfaces. It took the use of the same texture for both
normal surfaces and water surfaces to trigger the bug. Thanks go to Simon
'Sock' O'Callaghan and his In The Shadows mod.

libs/video/renderer/glsl/glsl_bsp.c

@@ -1132,6 +1132,8 @@ glsl_R_DrawWorld (void)
 						   quake_bsp.tlst.location,
 						   quake_bsp.color.location);
 		}
+		tex->elechain = 0;
+		tex->elechain_tail = &tex->elechain;
 	}
 	bsp_end ();
 }